Christopher R. J. Kilburn is Professor of Volcanology and Geophysical Hazards at University College London. Bill McGuire is Emeritus Professor of Earth Sciences at UCL. John Murray is a volcanologist best known for his work on Mt Etna and other active volcanoes. He was educated at Magdalene College Cambridge, and is presently based at the School of Environment, Earth and Ecosystems, Open University, UK.